Search results for "Monooxygenase"

Cytolytic T cell reactivity against melanoma-associated differentiation antigens in peripheral blood of melanoma patients and healthy individuals

1996

Antigenic peptides derived from several differentiation antigens of the melanocyte lineage were recently identified in human melanomas as targets for HLA-A2.1-restricted cytotoxic T lymphocytes (CTLs). To examine their potential role in tumour-directed immune responses in vivo, we determined CTL reactivity against seven antigenic peptides derived from the Melan A/MART-1, tyrosinase and gp100/Pmel17 antigens in the peripheral blood of 10 HLA-A2+ healthy controls and 26 HLA-A2+ melanoma patients. The influenza matrix peptide (GILGFVFTL) presented by HLA-A2.1 was used as a control peptide. CTL reactivity was assessed in a mixed lymphocyte 'peptide' culture assay. Reactivity against Melan A/MAR…

Partial tyrosinase-specific self tolerance by HLA-A*0201-restricted cytotoxic T lymphocytes in mice and man

2003

The human tyrosinase (hTyr) (369-377) cytotoxic T lymphocyte (CTL) epitope is presented by malignant melanoma and various nontransformed cells in association with human leukocyte antigen (HLA)-A*0201 (A2.1) and used for vaccination-based immunotherapy of melanoma patients. Its mouse homologue, mTyr (369-377), is naturally processed and bound by A2.1 with equivalent efficacy and thus enabled us to explore the effect of self tolerance on Tyr-specific T cells in different lines of A2.1 transgenic (Tg) mice and man. We found that self Tyr-reactive CTL in Tg mice and, importantly, in man were affected by partial tolerance resulting in only residual T lymphocytes of higher avidity for self Tyr al…

Long-term freedom from recurrence in 2 stage IV melanoma patients following vaccination with tyrosinase peptides.

2002

We report here on 2 patients who received adjuvant vaccination with an HLA-A2- or HLA-A24-restricted tyrosinase peptide, respectively, and GM-CSF for frequently relapsing stage IV melanoma. Following resection of metastases and irradiation of brain metastases in 1 patient, both patients were without evidence of disease when receiving the first vaccination. While the patients had had 9 and 12, respectively, mostly s.c., relapses during the 3 years before vaccination, they experienced freedom from relapse for more than 2 years after vaccination. We found a T-cell response to the vaccine peptide in both patients in the peripheral blood by ex vivo IFN-gamma ELISPOT assay. The T-cell population …

Melanoma-Reactive Class I-Restricted Cytotoxic T Cell Clones Are Stimulated by Dendritic Cells Loaded with Synthetic Peptides, but Fail to Respond to…

2003

Abstract Immunization with heat shock proteins (hsp) isolated from cancer cells has been shown to induce a protective antitumor response. The mechanism of hsp-dependent cellular immunity has been attributed to a variety of immunological activities mediated by hsp. Hsp have been shown to bind antigenic peptides, trim the bound peptides by intrinsic enzymatic activity, improve endocytosis of the chaperoned peptides by APCs, and enhance the ability of APCs to stimulate peptide-specific T cells. We have investigated the potential capacity of hsp70 and gp96 to function as a mediator for Ag-specific CTL stimulation in an in vitro model for human melanoma. Repetitive stimulation of PBLs by autolog…

Bioinspired self-assembly of tyrosinase-modified silicatein and fluorescent core-shell silica spheres.

2014

Inspired by the intermolecular cross-linking of mussel foot proteins and their adhesive properties, tyrosinase has been used to modify recombinant silicatein. DOPA/DOPAquinone-mediated cross-linking and interfacial interactions enhanced both self-assembly of silicatein building blocks and templating of core–shell silica spheres, resulting in fluorescent biomimetic silicatein–silica hybrid mesofibers.

Hemocyanin conformational changes associated with SDS-induced phenol oxidase activation.

2007

The enzymatic activity of phenoloxidase is assayed routinely in the presence of SDS. Similar assay conditions elicit phenoloxidase activity in another type 3 copper protein, namely hemocyanin, which normally functions as an oxygen carrier. The nature of the conformational changes induced in type 3 copper proteins by the denaturant SDS is unknown. This comparative study demonstrates that arthropod hemocyanins can be converted from being an oxygen carrier to a form which exhibits phenoloxidase activity by incubation with SDS, with accompanying changes in secondary and tertiary structure. Structural characterisation, using various biophysical methods, suggests that the micellar form of SDS is …

Functional Changes in the Family of Type 3 Copper Proteins During Evolution

2004

Isoenzyme-specific phosphorylation of cytochromes P-450 and other drug metabolizing enzymes.

1987

Abstract A series of fourteen cytochrome P-450 isoenzymes was treated with three different protein kinases and found to devide into isoenzymes phosphorylated (i) by both the cyclic AMP-dependent kinase and the calcium-phospholipid-dependent kinase (P-450 PB 3a and PB 2e), (ii) by none of these kinases (P-450 PB 1b, MC 1b, UT 1, and thromboxane synthase), and (iii) by either the cyclic AMP-dependent kinase (P-450 LM 2, PB 2d, and PB 3b) or the calcium-phospholipid-dependent kinase (P-450 PB 1a, PB 2a, MC 1a, LM 3c, and LM 4). Other components of the monooxygenase system, cytochrome P-450 reductase, cytochrome b5, cytochrome b5 reductase as well as microsomal epoxide hydrolase, were poor subs…

Separation and Biochemical Characterization of Rat Liver Parenchymal Cell Subpopulations

1988

Parenchymal cells within the hepatic lobules of the rat are morphologically and biochemically heterogeneous (Shank et al., 1959; Novikoff, 1959; Loud, 1968; Jungermann and Katz, 1982). It has been previously shown that the concentration of cytochrome P-450 and the activities of most cytochrome P-450-dependent monooxygenases are relatively higher in the centrilobular regions than in the periportal regions of the rat liver (Baron et al., 1978; Gooding et al., 1978; Baron and Kawabata, 1983); further, these studies revealed that pretreatment of the animals with phenobarbital intensified this gradation across the liver lobule, whereas after administration of 3-methylcholanthrene the concentrati…

Structure-Activity Relations of Flavonoids as Antimutagens Against Cooked Food Mutagens and Nitroarenes in the Salmonella Reversion Assay

1997

When about 60 flavonoids were tested for their antimutagenic potencies against 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) and the nitroarenes 2-nitrofluorene (2-NF), 1-nitropyrene (1-NP), and 3-nitrofluoranthene (3-NFA) in the Salmonella reversion assay, distinct structure-activity relations were detected. With both groups of compounds, flavonoid glycosides were inactive or at best weakly active. Catechins and anthocyanidins, which lack the carbonyl function at C-4 of the flavane nucleus, were inactive. In contrast, chalcones exerted strong antimutagenicity against IQ and the nitroarenes. With respect to IQ, flavonoids of low polarity were the most active compounds: The parent compounds …